The present invention is related to Japanese patent application No. 2001-71408, filed Mar. 14, 2001, the contents of which are incorporated herein by reference.
The present invention relates to an automatic headlight aiming device, and more particularly to an automatic headlight aiming device that automatically adjusts the direction of the vehicle headlights optical axis.
In conventional vehicle headlights, oncoming vehicle drivers are blinded if the direction of the headlight optical axis is directed upward by the vehicle body inclination. Alternatively, if directed downward, the driver""s distance visibility is reduced. Therefore, there is a demand for keeping the headlight optical axis fixed.
There is also conventional headlight adjusting device capable of controlling the range of light projection of the headlights according to information from a car navigation system mounted in the vehicle. This type of control device controls the headlight optical axis direction according to map information given by the car navigation system. However, it is difficult to control the headlight optical axis direction corresponding to actual road conditions because of various errors.
There is also a conventional system which recognizes a reference point on the car ahead after image processing by a CCD camera estimates conditions of the car ahead. Such a system is disclosed in JP-A-7-32936. It then controls a headlight optical axis based on the detected road conditions.
However, this system uses the largest point of illumination on the car ahead to decide the reference point. As such, sometimes this camera catches a bright street light or other illuminated object instead of the vehicle. Moreover, this system is only useful at night.
The present invention provides an automatic headlight aiming device that adjusts the vehicle""s driving environment according to information including cars ahead, while allowing deviation from a control angle in ordinary control for holding the optical axis of the headlights in a fixed direction.
In one aspect of the invention, the inclination angle of the headlight optical axis from the road surface is computed by the inclination angle computing means by referencing the vehicle information detecting means which detects the inclination information of a vehicle, movement information, and acceleration information. Then, the headlight optical axis is adjusted by the optical axis adjusting means, with reference to the optical axis center angle determined by correcting and computing the inclination angle by the optical axis center angle computing means according to the front information fed from the front information detecting means. That is, road information in the direction of vehicle travel is detected by the vehicle information detecting means. The presence or absence of a car ahead, distance between vehicles, and upward and downward behavior variations are detected by the front information detecting means. Therefore, beside a normal control by the inclination angle obtained from the vehicle information, the adjustment of the optical axis is performed, when needed, by referring to road information and the optical axis center angle after correction by a behavior change of a car ahead. It is therefore possible to improve the driver""s visibility of a forward road condition and a car ahead when changing to correct the normal control of the headlight optical axis direction without blinding the driver in the car ahead.
In another aspect, the center angle of the optical axis is computed by the optical axis center angle computing means after correction by using the horizontal and vertical displacement of the car ahead. When a specific threshold value is exceeded, the inclination angle is corrected to compute the center optical axis angle. Thus, the headlight optical axis direction is properly corrected without causing the driver to feel uncomfortable.
In another aspect, when the horizontal displacement of the car ahead exceeds a predetermined value, the range of light projection is changed according to the vehicle""s turning direction by the horizontal adjusting means. The horizontal adjusting means adjusts the headlight optical axis in the horizontal direction.
In another aspect, when the displacement exceeding the predetermined value is detected by a horizontal change of the car ahead, the right front or left front supplementary lamp of the vehicle is lit to widen the range of light projection.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.